This is an NIH grant application for support of a Keystone Symposia entitled "Conference on Diabetes Mellitus" to be held in the year 2000. Approximately every three years diabetes in the basic research which underlies it have served as a topic for a major Keystone Symposium which is held concurrently with a second symposium in the area of obesity and adipocyte differentiation. The conference will be initiated with a plenary lecture by Mike Brown or Joe Goldstein on molecular and genetic aspects of complex metabolic disorders and include sessions on leptin and leptin signaling, upstream and downstream components of the insulin action cascade (including glucose transporter regulation and gene expression), the role of PPARgamma in energy homeostasis, beta cell signaling in gene expression, genes of obesity and diabetes, and new targets for drug development. Based on previous symposia of this type, it is estimated that between 150250 people will attend, including numerous academic scientists, graduate students, and postdoctoral fellows, and some scientists from the pharmaceutical industry. At least four of the sessions will be held in conjunction with the simultaneous meeting on obesity and adipogenesis, and participants of both meetings will be allowed to attend sessions of either meeting. This is an important interaction, since the two fields are so closely related. In general, Keystone Symposia on Diabetes and Obesity are the most highly regarded basic science meetings in this area.